My wife's Centrino laptop just had its hard drive replaced, and I was setting it up so it could reconnect to my wireless ADSL. Weirdness ensued. First it connected straight away to my neighbour's wireless ADSL. When I went to disconnect in View Available Wireless Networks (which always used to show mine and the neighbour's), I got: "No wireless networks were found in range". The only way I could disconnect was to disable the wireless. Then I temporarily disabled my encryption and Mac address filtering, re-enabled the wireless and it connected right away to my router (stronger signal) but still with nothing showing in Available Wireless Networks. As soon as I re-enabled encryption the laptop would just connect to the neighbour's again, no way to force it to try to connect to mine & bring up the password dialogue.
Incidentally, the laptop's MAC address had changed too - when I re-enabled address filtering in my router it wouldn't connect until I discovered and entered in the new Mac address of the laptop. Changing a HD shouldn't have changed this, should it? Does this indicate they've swapped it for an entirely different unit?
So now the only security I have is the MAC address filtering which I'm obviously not comfortable with. Any ideas why it should be happily connecting but showing no available networks? I read a recommendation to disable SSID broadcast in the router as a security measure, and maybe this could cause the networks to not show up, but I doubt it because [a] my router manufacturer D-Link told me this couldn't be disabled in my unit (DSL G604-T) and [b] what a coincidence that my neighbour would suddenly disable his at the same time that mine's gone, when he doesn't seem to know or care about security at all! Oh, and [c] the name of my router (or my neighbour's) shows up in Settings>Network Connections>Wireless Network Connection>Details when connected.